Adam Young shared a patch to convert the tree back to a linear list: https://review.openstack.org/#/c/205266/
This shouldn't be merged without benchmarking as it's purely a performance-oriented change. On Thu, Jul 23, 2015 at 11:40 AM, Matt Fischer <m...@mattfischer.com> wrote: > Morgan asked me to post some of my numbers here. From my staging > environment: > > With 0 revocations: > Requests per second: 104.67 [#/sec] (mean) > Time per request: 191.071 [ms] (mean) > > With 500 revocations: > Requests per second: 52.48 [#/sec] (mean) > Time per request: 381.103 [ms] (mean) > > I have some more numbers up on my blog post about this but that's from a > virtual test environment and focused on throughput. > > Thanks for the attention on this. > > On Thu, Jul 23, 2015 at 8:45 AM, Lance Bragstad <lbrags...@gmail.com> > wrote: > >> >> On Wed, Jul 22, 2015 at 10:06 PM, Adam Young <ayo...@redhat.com> wrote: >> >>> On 07/22/2015 05:39 PM, Adam Young wrote: >>> >>> On 07/22/2015 03:41 PM, Morgan Fainberg wrote: >>> >>> This is an indicator that the bottleneck is not the db strictly >>> speaking, but also related to the way we match. This means we need to spend >>> some serious cycles on improving both the stored record(s) for revocation >>> events and the matching algorithm. >>> >>> >>> The simplest approach to revocation checking is to do a linear search >>> through the events. I think the old version of the code that did that is >>> in a code review, and I will pull it out. >>> >>> If we remove the tree, then the matching will have to run through each >>> of the records and see if there is a match; the test will be linear with >>> the number of records (slightly shorter if a token is actually revoked). >>> >>> >>> This was the origianal, linear search version of the code. >>> >>> >>> https://review.openstack.org/#/c/55908/50/keystone/contrib/revoke/model.py,cm >>> >>> >>> >> What initially landed for Revocation Events was the tree-structure, >> right? We didn't land a linear approach prior to that and then switch to >> the tree, did we? >> >>> >>> >>> >>> >>> >>> >>> Sent via mobile >>> >>> On Jul 22, 2015, at 11:51, Matt Fischer <m...@mattfischer.com> wrote: >>> >>> Dolph, >>> >>> Per our IRC discussion, I was unable to see any performance >>> improvement here although not calling DELETE so often will reduce the >>> number of deadlocks when we're under heavy load especially given the >>> globally replicated DB we use. >>> >>> >>> >>> On Tue, Jul 21, 2015 at 5:26 PM, Dolph Mathews <dolph.math...@gmail.com> >>> wrote: >>> >>>> Well, you might be in luck! Morgan Fainberg actually implemented an >>>> improvement that was apparently documented by Adam Young way back in >>>> March: >>>> >>>> https://bugs.launchpad.net/keystone/+bug/1287757 >>>> >>>> There's a link to the stable/kilo backport in comment #2 - I'd be >>>> eager to hear how it performs for you! >>>> >>>> On Tue, Jul 21, 2015 at 5:58 PM, Matt Fischer <m...@mattfischer.com> >>>> wrote: >>>> >>>>> Dolph, >>>>> >>>>> Excuse the delayed reply, was waiting for a brilliant solution from >>>>> someone. Without one, personally I'd prefer the cronjob as it seems to be >>>>> the type of thing cron was designed for. That will be a painful change as >>>>> people now rely on this behavior so I don't know if its feasible. I will >>>>> be >>>>> setting up monitoring for the revocation count and alerting me if it >>>>> crosses probably 500 or so. If the problem gets worse then I think a >>>>> custom >>>>> no-op or sql driver is the next step. >>>>> >>>>> Thanks. >>>>> >>>>> >>>>> On Wed, Jul 15, 2015 at 4:00 PM, Dolph Mathews < >>>>> dolph.math...@gmail.com> wrote: >>>>> >>>>>> >>>>>> >>>>>> On Wed, Jul 15, 2015 at 4:51 PM, Matt Fischer <m...@mattfischer.com> >>>>>> wrote: >>>>>> >>>>>>> I'm having some issues with keystone revocation events. The bottom >>>>>>> line is that due to the way keystone handles the clean-up of these >>>>>>> events[1], having more than a few leads to: >>>>>>> >>>>>>> - bad performance, up to 2x slower token validation with about >>>>>>> 600 events based on my perf measurements. >>>>>>> - database deadlocks, which cause API calls to fail, more likely >>>>>>> with more events it seems >>>>>>> >>>>>>> I am seeing this behavior in code from trunk on June 11 using >>>>>>> Fernet tokens, but the token backend does not seem to make a difference. >>>>>>> >>>>>>> Here's what happens to the db in terms of deadlock: >>>>>>> 2015-07-15 21:25:41.082 31800 TRACE keystone.common.wsgi DBDeadlock: >>>>>>> (OperationalError) (1213, 'Deadlock found when trying to get lock; try >>>>>>> restarting transaction') 'DELETE FROM revocation_event WHERE >>>>>>> revocation_event.revoked_at < %s' (datetime.datetime(2015, 7, 15, 18, >>>>>>> 55, >>>>>>> 41, 55186),) >>>>>>> >>>>>>> When this starts happening, I just go truncate the table, but this >>>>>>> is not ideal. If [1] is really true then the design is not great, it >>>>>>> sounds >>>>>>> like keystone is doing a revocation event clean-up on every token >>>>>>> validation call. Reading and deleting/locking from my db cluster is not >>>>>>> something I want to do on every validate call. >>>>>>> >>>>>> >>>>>> Unfortunately, that's *exactly* what keystone is doing. Adam and I >>>>>> had a conversation about this problem in Vancouver which directly >>>>>> resulted >>>>>> in opening the bug referenced on the operator list: >>>>>> >>>>>> https://bugs.launchpad.net/keystone/+bug/1456797 >>>>>> >>>>>> Neither of us remembered the actual implemented behavior, which is >>>>>> what you've run into and Deepti verified in the bug's comments. >>>>>> >>>>>> >>>>>>> >>>>>>> So, can I turn of token revocation for now? I didn't see an >>>>>>> obvious no-op driver. >>>>>>> >>>>>> >>>>>> Not sure how, other than writing your own no-op driver, or perhaps >>>>>> an extended driver that doesn't try to clean the table on every read? >>>>>> >>>>>> >>>>>>> And in the long-run can this be fixed? I'd rather do almost >>>>>>> anything else, including writing a cronjob than what happens now. >>>>>>> >>>>>> >>>>>> If anyone has a better solution than the current one, that's also >>>>>> better than requiring a cron job on something like keystone-manage >>>>>> revocation_flush I'd love to hear it. >>>>>> >>>>>> >>>>>>> [1] - >>>>>>> http://lists.openstack.org/pipermail/openstack-operators/2015-June/007210.html >>>>>>> >>>>>>> >>>>>>> __________________________________________________________________________ >>>>>>> OpenStack Development Mailing List (not for usage questions) >>>>>>> Unsubscribe: >>>>>>> openstack-dev-requ...@lists.openstack.org?subject:unsubscribe >>>>>>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >>>>>>> >>>>>>> >>>>>> >>>>>> >>>>>> __________________________________________________________________________ >>>>>> OpenStack Development Mailing List (not for usage questions) >>>>>> Unsubscribe: >>>>>> openstack-dev-requ...@lists.openstack.org?subject:unsubscribe >>>>>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >>>>>> >>>>>> >>>>> >>>>> >>>>> __________________________________________________________________________ >>>>> OpenStack Development Mailing List (not for usage questions) >>>>> Unsubscribe: >>>>> openstack-dev-requ...@lists.openstack.org?subject:unsubscribe >>>>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >>>>> >>>>> >>>> >>>> >>>> __________________________________________________________________________ >>>> OpenStack Development Mailing List (not for usage questions) >>>> Unsubscribe: >>>> openstack-dev-requ...@lists.openstack.org?subject:unsubscribe >>>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >>>> >>>> >>> >>> __________________________________________________________________________ >>> OpenStack Development Mailing List (not for usage questions) >>> Unsubscribe: openstack-dev-requ...@lists.openstack.org >>> ?subject:unsubscribe >>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >>> >>> >>> >>> __________________________________________________________________________ >>> OpenStack Development Mailing List (not for usage questions) >>> Unsubscribe: >>> openstack-dev-requ...@lists.openstack.org?subject:unsubscribehttp://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >>> >>> >>> >>> >>> __________________________________________________________________________ >>> OpenStack Development Mailing List (not for usage questions) >>> Unsubscribe: >>> openstack-dev-requ...@lists.openstack.org?subject:unsubscribehttp://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >>> >>> >>> >>> >>> __________________________________________________________________________ >>> OpenStack Development Mailing List (not for usage questions) >>> Unsubscribe: >>> openstack-dev-requ...@lists.openstack.org?subject:unsubscribe >>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >>> >>> >> >> __________________________________________________________________________ >> OpenStack Development Mailing List (not for usage questions) >> Unsubscribe: >> openstack-dev-requ...@lists.openstack.org?subject:unsubscribe >> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >> >> > > __________________________________________________________________________ > OpenStack Development Mailing List (not for usage questions) > Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev > >
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